Introduction
Heartworm disease can be a devastating condition for your dog. Early detection can mean the difference between life and death. Tests are available that can help to identify infestation by the heartworm parasite.
Testing for Heartworm Disease
Antibody tests are preferred for cats because they often have many fewer worms inside than dogs. A positive heartworm antibody test indicates that the animal most likely has an infection in progress (2-3 months at least).
The antigen test is more likely to have false-negatives, though false negatives can occur with the antibody test as well. However, if an antigen test is positive, it is usually a trusted result.
X-rays are of limited use in cats for definitive diagnosis since the infestations are usually low burden ones. Ultrasound of the heart and lungs has a much greater diagnostic capacity. Ultrasonographers can often see the worms in the right ventricle chamber of the heart, or in the pulmonary artery.